MXPA98007611A - Production of polyurethane foams - Google Patents

Abstract

Polyurethane foams are produced by reacting a) diisocyanates and / or organic and / or modified organic polyisocyanates, with b) at least one relatively high molecular weight compound containing at least two reactive hydrogen atoms, c) at least a compound contains from three to eight, preferably three to six reactive hydrogen atoms, and d) low molecular weight chain and / or crosslinking agents containing at least two reactive hydrogen atoms in the presence of e) swelling agents f) catalysts and, if desired, g) auxiliaries and auxiliary additives. wherein (c) are ethylene oxide-rich adducts having an ethylene oxide content of more than 50 weight percent, and an OH number of 200 to 800 milligrams of KOH per gram, and (d) are elongation agents. of polyfunctional chain and / or crosslinking having an OH number of more than 700 milligrams of KOH per gram. The polyurethane foam produced by this process can be used as a upholstery material

Description

"POLYURETHANE FOAM PRQDUCCLON" The present invention relates to a process for producing polyurethane foams by reacting "a) diisocyanates and / or organic and / or modified organic polyisocyanates with b) at least one relatively high molecular weight compound containing at least two carbon atoms. hydrogen reactants plus a combination of c) at least one compound containing three to eight, preferably three to six reactive hydrogen atoms, and d) low molecular weight chain lengthening agents and / or crosslinking agents containing at least two reactive hydrogen atoms in the presence of e) swelling agents f) catalysts and, if desired, g) auxiliaries and additional additives This process produces, in particular, flexible polyurethane foams having improved hardness and increased strength at wet thermal aging The production of polyurethane by reacting diisocyanates and / or organic polyisocyanates in compound s containing at least two reactive hydrogen atoms, for example, polyoxyalkylene polyamines and / or preferably organic polyhydroxyl compounds, in particular polyetherols having molecular weights of, for example, 300 to 6000 and, if desired, elongation agents of chain and / or crosslinking agents having molecular weights of up to about 400, in the presence of catalysts, swelling agents, flame retardants, auxiliaries and / or additives is known and has been described many times. A summary overview of the production of polyurethane foams is provided, for example in Kunststoff-Hanbuch, Volume III, "Polyurethane", First Edition, 1966, edited by Dr. R. Vieweg and Dr. A. Hochtlen, and Second Edition , 1983, and also Third edition, 1993 edited by Dr. G. Oertel (Cari Hanser of Verlag, Munich). There have been numerous publications on the subject of flexible foams having sufficient hardness which are also resistant to wet thermal aging. Thus, Patent Number EP-A-449609 discloses a highly elastic flexible foam in which an improvement in properties, particularly with respect to compression fit, is said to be achieved by increased proportions of 2,4-TDI. This makes it possible to reduce the proportions of the polymer polyol.

- - In Patent Number EP-A-346670, flexible block foams having a very low density at a low rate are produced. Here, a hexa-functional short-chain cross-linking polyol is mixed to achieve the necessary stabilization of the foam. Patent Number EP-A-496420 describes flame retardant flexible foams. Here, a combination of the short-chain cross-linking polyols containing nitrogen and a trifunctional polyol containing at least two secondary groups is claimed. The Patent Number WO 95/15990 describes the use of high functionality polyols, in particular hexa-functional for highly elastic flexible foams. Diethanolamine as a chain elongation agent / crosslinking agent in proportions up to 5 parts by weight is mentioned as an example. In the Patent Number EP-A-704468, high functionality polymer polyols are used for flexible foams. The formulations employed are directed, in particular, to the use according to the invention of relatively high proportions of diols as chain elongation agents. Patent Number EP-A-350868 claims a relatively high molecular weight high functionality polymer polyol. As the auxiliary polyol, use is made of a polyetherol having a molecular weight of 450 to 3000 and an ethylene oxide content of > 30 per cent. The sugar ethanolamine species is mentioned as crosslinking agents. Patent Number EP-A-406702 mentions ethylene glycerol ducts as crosslinking polyols, crosslinking agents having a functionality of 2 to 8 being claimed. The combinations with diethanolamine are claimed herein. As a result of the used cell opening polyols, it is said that a foam of very closed cells can be obtained in the index scale of 105 to 120. Patent Number EP-A-731120 mentions foams having improved moist thermal aging which are obtained by using a mixture of polyol which comprises less a polyol having a functionality of 3.5 to 8, and an ethylene oxide content of 10 percent to 30 percent and at least one polyetherol having a functionality of 2 to 8 and an ethylene oxide content of 50. percent to 95 percent. The alkanolamine derivatives are mentioned as crosslinking agents. The concomitant use of filling or loading materials is possible to increase the hardness. An object of the present invention is to provide polyurethane foams having hardness - improved and increased wet thermal resistance without deteriorating the other properties of the foam. We have found that this object is achieved by using, in addition to the customary component (b) comprising at least one relatively high molecular weight compound containing at least 2 reactive hydrogen atoms, a specific combination of at least one compound containing from 3 to 8, preferably from 3 to 6 reactive hydrogen atoms (c) and low molecular weight chain elongation agents and / or crosslinking agents containing at least 2 reactive hydrogen atoms (d) wherein the component (c) comprises adducts rich in ethylene oxide having an ethylene oxide content of more than 50 weight percent and an OH number of 200 to 800 milligrams of KOH per gram, and (d) are elongation agents polyfunctional chain and / or crosslinking agents having an OH number of more than 700 milligrams of KOH per gram. The present invention therefore provides a process for producing polyurethane foams by reacting (a) diisocyanates and / or organic and / or modified organic polyisocyanates with - - (b) at least one relatively high molecular weight compound containing at least two reactive hydrogen atoms, (c) at least one compound containing three to eight, preferably three to six reactive hydrogen atoms, and (d) chain lengthening agents and / or low molecular weight crosslinking agents containing at least two reactive hydrogen atoms in the presence of (e) catalyst swelling agents (f) and, if desired, (g) auxiliary additives, wherein (c) are adducts rich in ethylene oxide having an ethylene oxide content of more than 50 weight percent and an OH number of 200 to 800 milligrams of KOH per gram, and ( d) are chain-lengthening agents and / or polyfunctional crosslinking agents having an OH number of more than 700 milligrams of KOH per gram. The invention also provides the polyurethane foam produced by this process and provides information on its use as an upholstery material. In accordance with the present invention, the process for producing the polyurethane foams is carried out using, in addition to the customary components, a - specific combination of at least one compound containing from three to eight, preferably from three to six reactive hydrogen atoms (c) and low molecular weight chain and / or crosslinking agents containing at least two atoms of reactive hydrogen (d). As the component (c), use is made of adducts rich in ethylene oxide, preferably ethylene oxide adducts of glycerol, trimethylolpropane, pentaerythritol or any of the mixtures thereof. Suitable initiators for the ethylene oxide adducts are further, or as a mixture in the aforementioned compounds, of additional relatively high functionality initiators, for example, sorbitol, ditrimethylolpropane, triethanolamine, diethanolamine and mixtures thereof. It is also possible to use additional initiators having a functionality of 3 to 8. The ethylene oxide is reacted in the customary manner with the initiator or mixture of initiators. The OHN of these ethylene oxide adducts is within the range of 200 to 800 milligrams of KOH per gram, preferably 400 to 700, and in particular 500 to 700 milligrams of KOH per gram.

The ethylene oxide content of component c) is at least 50 weight percent, preferably more than 90 weight percent. Compounds (c) of relatively high functionality are preferably used in proportions of 0.5 percent to 10 percent by weight, particularly in proportions of 1 percent to 8 percent by weight, based on the weight of the components (b) ) a (g). As component (d), use is made of polyfunctional chain and / or crosslinking chain lengthening agents having an OH number of more than 700 milligrams of KOH per gram, preferably glycerol. It is also possible to use trimethylolpropane, pentaerythritol or mixtures of these compounds. In addition to these compounds used according to the present invention, small amounts of the customary chain-lengthening and / or cross-linking agents mentioned below can also be added. Component (d) is preferably used in proportions of 0.5 percent to 6 percent by weight, particularly preferably in proportions of 0.5 percent to 4 percent by weight, based on the weight of components (b) a (g) - - The molar ratio of (c) to (d) preferably lies within the range of 10 to 0.3, in particular 3.0 to 0.3. In a particularly preferred embodiment, the component (c) used is a trifunctional polyol based on ethylene oxide and having an OH number of 530 milligrams of KOH per gram (Lupranol® VP 9209) and an amount of 5 percent to 6 percent by weight and the component (d) used is glycerol, in an amount of 3 weight percent. In addition to the above-described combination of components (c) and (d), it is possible to use the starting materials customary in polyurethane chemistry to produce the polyurethane foams of the present invention. The following may be said by way of example about these other customary starting materials. a) organic and / or modified organic diisocyanates and / or polyisocyanates are the polyfunctional aliphatic, cycloaliphatic, araliphatic, and preferably aromatic isocyanates, known per se. Specific examples are: alkylene diisocyanates having from 4 to 12 carbon atoms in the alkylene radical, for example, 1,2-dodecane diisocyanate, 1,4-di-2-ethyl-tetramethylene diisocyanate, 1,5-diisocyanate 2-methylpentamethylene, 1,4-tetramethylene diisocyanate and preferably 1,6-hexamethylene diisocyanate; cycloaliphatic diisocyanates such as 1,3- and 1,4-cydohexane diisocyanate and also any of the mixtures of these isomers, l-isocyanato-3, 3, 5-trimethyl-5-isocyanatomethylcyclohexane (IPDI), 2,4- and 2,6-hexahydrolylene diisocyanate and also the corresponding isomer mixtures, 4,4'-, 2,2'- and 2,4'-dicyclohexylmethane diisocyanate and also the corresponding isomer mixtures, and preferably the diisocyanates and polyisocyanates aromatics such as 2,4- and 2,6-toluene diisocyanate (-TDI) and the corresponding isomer mixtures, 4,4'-, 2,4'- and 2, 2'-diphenylmethane diisocyanate (-MDI) and the corresponding isomer mixtures, mixtures of polyphenylmethylene polyisocyanates, mixtures of 4,4'-, 2,4'- and 2,20-MDI and polyphenylpoly ethylene polyisocyanates (crude MDI) and mixtures of crude MDI and TDI. The organic diisocyanates and polyisocyanates can be used individually or in the form of their mixtures. Modified polyfunctional isocyanates, that is, products obtained by chemical reaction of the diisocyanates and / or organic polyisocyanates, are also suitable. Examples that may be mentioned are diisocyanates and / or polyisocyanates which - they contain groups of ester, urea, biuret, allophanate, isocyanurate and preferably carbodiimide, uretonimine and / or urethane. Specific examples of suitable modified polyfunctional isocyanates are: prepolymers containing urethane groups and having an NCO content of 14 percent to 2.8 percent by weight, preferably 12 percent to 3.5 percent by weight, or pseudoprepolymers having an NCO content of 35 percent to 14 percent by weight, preferably 34 percent to 22 percent by weight, where the urethane-modified polyisocyanates derived from TDI have, in particular, an NCO content of 43 percent to 28 percent by weight, and those derived from 4,4'-MDI, 4,4'- and 2,4'-MDI which are mixtures of isomer or have crude MDI, in particular, an NCO content from 28 percent to 14 percent by weight, particularly preferably from 28 percent to 22 percent by weight based on total weight, and which are prepared by reacting diols, oxyalkylene glycols and / or polyoxyalkylene glycols having molecular weights from 62 to 6000, preferably from 134 to 4200 with TDI, 4,4'-MDI, mixtures of the MDI isomer and / or crude MDI, for example from 20 ° C to 110 ° C, preferably from 50 ° C_to 90 ° C with examples of oxyalkylene or polyoxyalkylene glycols which can be used individually as mixtures with diethylene glycol, dipropylene glycol, - - polyoxyethylene glycol, polyoxypropylene glycol and polyoxypropylene polyoxyethylene glycol; polyisocyanates containing carbodiimide groups and / or uretoimine groups, e.g. based on isomers of MDI and / or TDI. The modified polyisocyanates may be mixed with one another or with unmodified organic polyisocyanates such as 2,4'- and / or 4,4'-MDI, crude MDI, 2,4- and / or 2,6-TDI. . The organic polyisocyanates which have been found to be particularly useful and therefore preferably used are mixtures of TDI and crude MDI or mixtures of modified organic polyisocyanates containing urethane groups and having an NCO content of 44%. one hundred to 15 weight percent, in particular those based on TDI, 4,4'-MDI, mixtures of MDI isomers or crude MDI and in particular crude MDI having an MDI isomer content of 30 percent to 80 percent percent by weight, preferably from 30 percent to 55 percent by weight. b) as relatively high molecular weight compounds containing at least two reactive hydrogen atoms, use is advantageously made of those having a functionality of 2 to 4, preferably 2 to 3, and a molecular weight of 300 to 8000 , preferably from 300 to 5000.

Examples of the compounds that have been found to be useful are polyether polyamines and / or polyols which are preferably selected from the group consisting of polyether polyols, polyester polyols, polythioether polyols, polyesteramides, hydroxyl-containing polyacetals and aliphatic polycarbonates which contain hydroxyl or mixtures of at least two of the mentioned polyols. Preference is given to the use of polyester polyols and / or polyether polyols. The hydroxyl number of these polyhydroxyl compounds is generally from 20 to 80, and preferably from 28 to 56. Suitable polyester polyols can be prepared, for example, from organic dicarboxylic acids having from 2 to 12 carbon atoms, preference is given to aliphatic dicarboxylic acids having from 4 to 6 carbon atoms, and polyhydric alcohols, preferably diols having 2 to 12 carbon atoms, preferably 2 to 6 carbon atoms. Examples of suitable dicarboxylic acids are succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebasic acid, decandicarboxylic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid and terephthalic acid. The dicarboxylic acids can be used either individually or in admixture with one another. Instead of the free dicarboxylic acids, it is also possible to use the corresponding dicarboxylic acid derivatives such as the dicarboxylic esters of alcohols having from 1 to 4 carbon atoms, or dicarboxylic anhydride. Preference is given to the use of dicarboxylic acid mixtures of succinic, glutaric and adipic acids in weight ratios, for example, 20-35: 35-50: 20-32, and in particular, adipic acid. Examples of the dihydric and polyhydric alcohols, in particular diols, are ethanediol, diethylene glycol, 1,2- and 1,3-propanediol, dipropylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, , 10-decanodiol, glycerol and trimethylolpropane. Preference is given to the use of ethanediol, diethylene glycol, 1,4-butanediol, 1,5-pentanediol and 1,6-hexanediol. It is also possible to use the polyester polyols derived from lactones, e.g. epsilon-caprolactone or hydroxycarboxylic acids, e.g. acid or ega-hydroxycaproic acid. To prepare the polyester polyols, the organic polycarboxylic acids e.g. aromatics and preferably aliphatics and / or the polyhydric derivatives and alcohols can be polycondensed in the absence of catalysts or preferably in the presence of esterification catalysts advantageously in an almost inert atmosphere, e.g. nitrogen, carbon monoxide, helium, argon, etc. in melting at a temperature of 150 ° C to 250 ° C, preferably 18 ° C to 220 ° C under atmospheric pressure at reduced pressure towards the desired acid number which is advantageously less than 10, preferably less than 2. According to a preferred embodiment, the esterification mixture is polycondensed at the above mentioned temperatures up to an acid number of 80 to 30, preferably of 40 to 30, under atmospheric pressure and subsequently under a pressure of less than 500 mbar, preferably from 50 to 150 mbar. Examples of suitable stexification catalysts are the catalysts of iron, cadmium, cobalt, lead, zinc, antimony, magnesium, titanium, tin in the form of metals, metal oxides or metal salts. However, polycondensation can also be carried out in the liquid phase in the presence of diluents and / or entraining agents such as benzene, toluene or xylene or chlorobenzene to azeotropically distill water from the condensation. To prepare the polyester polyols, the organic polycarboxylic acids and / or polyhydric alcohol derivatives are advantageously polycondensed in a molar ratio of 1: 1 to 1.8, preferably 1: 1.05 to 1.2. The polyester polyols obtained preferably have a functionality of 2 to 4, in particular of 2 to 3, and a molecular weight of 480 to 3000, in particular of 600 to 2000.

However, the polyols which are particularly preferably used are the polyether polyols which are prepared by known methods, for example, of one or more alkylene oxides having from 2 to 4 carbon atoms in the alkylene radical, by anionic polymerization using alkali metal hydroxides such as sodium or potassium hydroxide or alkali metal alkoxides such as sodium methoxide, sodium or potassium ethoxide or potassium isopropoxide, as catalysts with addition of at least one initiator molecule containing 2 to 4, preferably 2 to 3 reactive hydrogen atoms in bound form or by cationic polymerization using Lewis acids, such as antimony pentachloride, boron fluoride etherate, etc. or bleaching earth as catalysts. For specific applications, the monofunctional initiators can also be incorporated into the polyether structure. Suitable alkylene oxides are, for example, tetrahydrofuran, 1,3-propylene oxide, 1,2- or 2,3-butylene oxide, styrene oxide and preferably ethylene oxide and 1,2-propylene oxide. . The alkylene oxides can be used individually, alternatively in succession or as mixtures. Examples of suitable initiator molecules are: water, organic dicarboxylic acids such as succinic acid, adipic acid, phthalic acid and terephthalic acid, aliphatic and aromatic non-alkylated, N-monoalkylated, N, N-dialkylated and N, N'-dialkylated diamines having from 1 to 4 carbon atoms in the alkyl radical, for example, unalkylated, monoalkylated and dialkylated ethylenediamine, diethylene triamine, triethylene tetramine, 1,3-propylene diamine, 1,3- or 1,4-butylene diamine, 1,2 -, 1,3-, 1,4-, 1,5- and 1,6-hexamethylenediamine, phenyldenediamine, 2,3-, 2,4- and 2,6-tolylenediamine and 4,4'-, 2,4 '- and 2, 2' -diaminodiphenylmethane. Additional suitable starter molecules are: alkanolamines, such as ethanolamine, N-methylethanolamine and N-ethylentanolamine, dialkanolamines such as diethanolamine, N-methyldiethanolamine and N-ethylenediethanolamine, and trialkanolamines such as triethanolamine and ammonia. Preference is given to the use of polyhydric alcohols, in particular, dihydric and / or trihydric alcohols such as ethanediol, 1,2- and 2,3-propanediol, diethylene glycol, dipropylene glycol, 1,4-butanediol, 1,6-hexanediol, glycerol, trimethylolpropane and pentaerythritol. The polyether polyols, preferably polyoxypropylene polyols and polyoxypropylene-polyoxytelene polyols have a functionality preferably of 2 to 4, and in particular of 2 to 3, and molecular weights of 300 to 8000, preferably 300 to 6000, and in particular from 1000 to 5000, and appropriate polyoxytetramethylene glycols have a molecular weight of up to about 3500. Polyether-modified polyethers, preferably polyether polyether polyols, in particular those based on styrene and / are also suitable as polyether polyols. or acrylonitrile which are prepared by the in situ polymerization of acrylonitrile, styrene or preferably mixtures of styrene and acrylonitrile, eg in a weight ratio of 90:10 to 10:90, preferably from 70:30 to 30:70, advantageously in the aforementioned polyether polyols as described in German Patent Nos. 1111394, 1222669 (US-A-3304273) , 3383351, 3523093), 1152536 (GB 1040452) and 1152537 (GB 987618), and also polyether polyol dispersions containing as the dispersed phase, customarily in an amount of 1 percent to 50 percent by weight, preferably from 2 percent to 25 percent by weight, eg polyureas, polyhydrazides, polyurethanes containing bound tertiary amine groups and / or melamine, and which are described, for example, in Patent Number EP-B-011752 (US-A-4304708), US Patent Number A-4374209 and Patent Number DE-A-3231497. Like the polyester polyols, the polyether polyols can be used individually or in the form of mixtures. You can also mix with polyether graft polyols or polyester polyols or with hydroxyl-containing polyester amides, polyacetals, polycarbonates and / or polyether polyamines. Suitable polyacetals containing hydroxyl are, for example, compounds that can be prepared from glycols such as diethylene glycol, triethylene glycol, 4,4'-dihydroxyethoxydiphenyldimethylmethane, hexanediol and formaldehyde. The appropriate polyacetals can also be prepared by polymerization of the cyclic acetals. Suitable hydroxyl-containing polycarbonates are those of the type known per se which can be prepared, for example, by making diol reactions such as 1,3-propanediol, 1,4-butanediol and / or 1,6-hexanediol, diethylene glycol, triethylene glycol or tetraethylene glycol with diaryl carbonates, eg diphenyl carbonate or phosgene. Polyester amides include, for example, predominantly linear condensates obtained from saturated and / or unsaturated polybasic carboxylic acids, or their anhydrides and polyfunctional saturated and / or unsaturated amino alcohols or mixtures of polyfunctional alcohols and aminoalcohols and / or polyamines. Suitable polyether polyamines can be prepared from the aforementioned polyether polyols by known methods. Examples which may be mentioned are the cyanoalkylation of polyoxyalkylene polyols and the subsequent hydrogenation of the formed nitrile (US Patent Number 3 ~ 267050) or the partial or complete amination of polyoxyalkylene polyols with amines or ammonia, in the presence of hydrogen and catalysts ( Patent Number DE-A-1215373). c) In accordance with the present invention, the production of the polyurethane foams is carried out using adducts rich in ethylene oxide, as described above, as compounds containing from 3 to 8, preferably from 3 to 6 reactive hydrogen atoms. d) The above-described chain and / or crosslinking elongation agents are used to produce the polyurethane foams of the present invention. However, the addition of additional chain elongation agents, additional crosslinking agents or, if desired, mixtures thereof, can prove to be advantageous for modifying the mechanical properties. As the additional chain and / or crosslinking agents, use is made of diols and / or triols having molecular weights of less than 400, preferably from 60 to 300. Examples of chain elongation / crosslinking agents Suitable are aliphatic, cycloaliphatic and / or araliphatic diols having from 2 to 14, preferably from 4 to 10, carbon atoms, eg ethylene glycol, 1,3-propanediol, 1,2-decanediol, o-, m-, p-hydroxycyclohexane, diethylene glycol, dipropylene glycol and preferably 1,4-butanediol, 1,6-hexanediol and bis- (2-hydroxyethyl) hydroquinone , triols such as 1,2,4- and 1, 3, 5-trihydroxycyclohexane and polyalkylene oxides containing low molecular weight hydroxyl based on ethylene oxide and / or 1,2-propylene oxide and the diols and / or triols previously mentioned as starter molecules. If additional chain elongation agents, crosslinking agents or mixtures thereof are used to produce the polyurethane foams, these are present in an amount of from 0 percent to 20 percent by weight. e) As swelling agents, it is possible to use chlorofluorocarbons (CFCs) and highly fluorinated and / or perfluorinated hydrocarbons known from polyurethane chemistry. However, due to ecological reasons, the use of these materials is being greatly restricted or completely stopped. Alternative blowing agents are, in addition to HCFCs and HFCs, in particular, aliphatic and / or cycloaliphatic hydrocarbons, in particular pentane and cyclopentane, or acetals, such as methylal. These physical swelling agents are usually added to the polyol component of the system. However, they can also be added to the diisocyanate component or both the polyol component and the diisocyanate component. They can also be used together with highly fluorinated and / or perfluorinated hydrocarbons in the form of an emulsion of the polyol component. If emulsifiers are used, oligomeric acrylates containing linked polyoxyalkylene and fluoroalkane radicals are used as side groups and have a fluorine content of about 5 percent to 30 percent by weight. These products are sufficiently well known in plastics chemistry, e.g. EP-A 351614. The amount of the swelling agent or swelling agent mixture used is from 1 percent to 25 percent by weight, preferably from 1 percent to 15 percent by weight in each case based on the components (b) to (g). In addition, it is possible and customary to add water as the swelling agent in the forming component (b) in an amount of 0.5 percent to 15 percent by weight, preferably 1 percent to 5 percent by weight based on the components trainers (b) to (g). The addition of water can be carried out in combination with the use of the other described swelling agents. f) The catalysts used to produce polyurethane foams are in particular the compounds which intensely accelerate the reaction of the compounds containing the reactive hydrogen atoms, in particular the hydroxyl groups of the components (b), (c) and (d) ) with the modified or unmodified organic polyisocyanates (a). Suitable catalysts are the organic metal compounds, preferably organic tin compounds such as tin (II) salts, of the organic carboxylic acids, e.g. tin (II) acetate, tin (II) octoate, tin (II) ethylhexanoate and tin (II) laurate, and dialkyltin (IV) salts of organic carboxylic acids, e.g. and dibutyltin acetate, and dibutyltin laurate, dibutyltin maleate and dioctyltin diacetate. The organic metal compounds are used alone or preferably in combination with intensely basic amines. Examples that may be mentioned are amidines, such as 2,3-dimethyl-3,4,5,6-tetrahydropyrimidine, tertiary amines such as triethylamine, tributyl amine, dimethylbenzylamine, N-methylmorpholine, N-ethylmorpholine, N-cyclohexylmorpholine, N, N, N ', N' -tetramethylethylenediamine, N, N, N ', N'-tetramethylbutanediamine, N, N, N', N '-tetramethylhexan-1,6-diamine, pentamethyldiethylenetriamine, bis (dimethylaminoethyl) ether, bis ( dimethylaminopropyl) urea, dimethylpiperazine, 1,2-dimethylimidazole, 1-azabicyclo [3.3.0] octane, and preferably 1,4-diazabicyclo [2.2.2] octane, and the alkanolamine compounds such as triethanolamine, triisopropanolamine, N- methyldiethanolamine and N-ethyldiethanolamine and dimethylethanolamine. Additional suitable catalysts are: tris (dialkylaminoalkyl) -s-hexahydrotriazines, in particular, tris (N, N-dimethylaminopropyl) -s-hexahydrotriazine, tetraalkylammonium hydroxides such as tetramethylammonium hydroxide, alkali metal hydroxides such as sodium hydroxide and alkali metal alkoxides such as sodium methoxide and potassium isopropoxide, and also alkali metal salts of long chain fatty acids having from 10 to 20 carbon atoms and possibly side OH groups. Preference is given to the use of 0.001 percent to 5 percent by weight, in particular 0.05 percent to 2 percent by weight of a catalyst or combination of catalysts based on the weight of the forming components (b) to (g) . g) If desired, additional auxiliaries and / or additives may be incorporated into the reaction mixture to produce the polyurethane foams. Examples that may be mentioned are flame retardant agents, surfactants, foam stabilizers, cell regulators, fillers or fillers and dyes, pigments, hydrolysis inhibitors, fungistatic and bacteriostatic substances.

Suitable flame retardants are, for example, tricresyl phosphate, tris (2-chloroethyl) phosphate, tris (2-chloropropyl) phosphate, tetrakis (2-chloroethyl) ethylene diphosphate, dimethyl methanphosphonate, diethyldiethanolaminomethylphosphonate and also flame retardant polyols which they contain commercial halogens. In addition to the aforementioned halogen-substituted phosphates, it is also possible to use inorganic or organic flame retardants such as red phosphorus, hydrous aluminum oxide, antimony trioxide, arsenic oxide, ammonium polyphosphate and calcium sulfate, graphite derivatives or expandable cyanuric acid. such as melamine, or mixtures of at least two flame retardant agents such as ammonium polyphosphate and melamine and also, if desired, corn starch or ammonium polyphosphate, melamine and expandable graphite and / or aromatic or aliphatic polyesters to produce polyisocyanate flame retardant polyaddition products. The melamine additions are found to be particularly effective. It has generally been found to be advantageous to use from 5 to 50 parts by weight, preferably from 5 to 25 parts by weight, of the above-mentioned flame retardants per 100 parts by weight of the forming components (b) to (g). Suitable surface-active substances are, for example, compounds which serve to assist the homogenization of the starting materials and may also be suitable for regulating the structure of the plastics cell. Examples which may be mentioned are emulsifiers such as the sodium salts of the castor oil sulfates of the fatty acids and also the amine salts of the fatty acids, e.g. dimethiamine oleate, diethanolamine stearate, diethanolamine ricinoleate, sulfonic acid salts e.g. alkali or ammonium salts of dodecylbenzene or dinaphthylmetanedisulfonic acid and ricinoleic acid; foam stabilizers such as siloxane-oxyalkylene copolymers and other ethoxylated alkylphenols and organopolysiloxanes, ethoxylated fatty alcohols, paraffin oils, castor oil or ricinoleic esters, turkey red oil and peanut oil and cell regulators, such as paraffins, alcohols fatty acids and dimethylpolysiloxanes. The above-described oligomeric acrylates having polyoxyalkylene and fluoroalkylene radicals as secondary groups are also suitable for improving the emulsifying action, the structure of the cell and / or for stabilizing the foam. The surface-active substances are usually used in amounts of 0.01 to 5 parts by weight based on 100 parts by weight of the forming components (b) to (g).

- - For the purposes of the present invention, the filler or filler materials, in particular the filler or reinforcing filler materials are customary organic and inorganic fillers or fillers, reinforcing materials, weighting agents, agents to improve the performance of abrasion in paints, coatings, etc. that are known per se. Specific examples are: inorganic fillers or fillers such as silicon minerals, for example, sheet silicates such as antiborite, serpentine, hornblende, amphibole, chrysotile, talc; metal oxides such as kaolin, aluminum oxides, titanium oxides and iron oxides, metal salts, for example, clay, barite and inorganic pigments such as cadmium sulfide, zinc sulphide and also glass, etc. Preference is given to using kaolin (China clay), aluminum silicate and co-precipitates of barium sulfate and aluminum silicate and also natural and synthetic fibrous materials such as wollastonite, metal and in particular glass fibers of various lengths which can to dress with a sizing. Suitable organic fillers or fillers are, for example: carbon, rosin, cyclopentadienyl resins and graft copolymers and also cellulose fibers, polyamide fibers, polyacrylonitrile fibers, polyurethane fibers, polyester fibers based on the aromatic and / or aliphatic dicarboxylic esters and, in particular, carbon fibers. The inorganic and organic fillers can be used individually as mixtures and are advantageously incorporated into the reaction mixture in amounts of 0.5 percent to 50 percent by weight, preferably 1 percent to 40 percent by weight based on the weight of the components (a) to (g), but the content of the mats, non-woven and woven fabrics of natural and synthetic fibers can reach values up to 80 weight percent. Additional details related to the customary auxiliaries and additives mentioned above can be found in the specialized literature, for example, of the J.H. Saunders and K.C. Frisch "High Polymers", Volume XVI, Polyurethanes, Parts 1 and 2, Interscience Publishers, 1962 and 1964, or the Kunststoffhandbuch, Poiyurethanes, Volume VII, Hanser-Verlag of Munich, Vienna, Ira. 2nd and 3rd. editions of 1966, 1983 and 1993. - In order to produce the polyurethane foams, the components (a) to (g) are reacted in quantities such that the equivalence ratio of the NCO groups of component (a) to the The sum of the reactive hydrogen atoms of the components (b) to (g) is 0.60-1.25: 1, preferably 0.90-1.15: 1.

The polyurethane foams produced by the process of the present invention are advantageously produced by the one-shot method, for example, by means of a high pressure or low pressure technique, in open or closed molds, for example, metal molds . The continuous application of the reaction mixture on the appropriate conveyor belts to produce blocks of foam is also customary. It has been found to be particularly advantageous to employ the two component method and combine the forming components (b), (c), (d), (e), (f) and if (g) is used, to form a component of polyol, often also referred to as component A, and using the forming component (a) and, if desired, the swelling agents (c) as the isocyanate component are often also referred to as component B. The starting components are mixed at a temperature of 15 ° C to 90 ° C, preferably 20 ° C to 60 ° C, and in particular of 20 ° C to 35 ° C and introduced into the mold open or under atmospheric pressure or superatmospheric pressure inside the closed mold or , in the case of a continuous work station they are applied to a belt and the reaction mixture is accommodated. The mixing can be carried out mechanically by means of an agitator, by means of a stirring spoon by means of high pressure mixing in a nozzle. The temperature of the mold is advantageously from 20 ° C to 110 ° C, preferably from 30 ° C to 65 ° C, and in particular from 35 ° C to 65 ° C. The polyurethane foams produced by the process of the present invention have a density of 100 to 800 kilograms per cubic meter, preferably 35 to 70 kilograms per cubic meter and in particular, 25 to 50 kilograms per cubic meter. They are particularly suitable as upholstery material in the furniture and car seat sectors, but also, with correspondingly higher foam densities, as integral foam components in automotive safety applications. They are particularly suitable for use in climatic regions having a high atmospheric humidity where the corresponding resistance is absolutely necessary. They are also suitable, in the case of relatively low densities, to produce foams which, despite the lower density, have sufficiently good mechanical properties and maintain them over a prolonged period of time. The present invention is illustrated by the examples that are presented below without being restricted by them.

Example 1-4 (Comparison Examples) Example Example Example Example 1 2 3 4 Lupranol® 2042 60.05 57.95 56.90 63.10 Lupranol® 4100 30.00 30.00 30.00 30.00 Glycerol 1.00 3.00 4.00 Diethylene glycol 2.00 2.00 2.00 Triethanolamine 3.20 Lupranol® 2047 3.00 3.00 3.00 Lupragen® N201 0.40 0.50 0.55 0.15 Lupragen® N206 0.25 0.25 0.25 0.25 B 8680 0.30 0.30 0.30 0.30 Water 3.00 3.00 3.00 3.00 FD (core) 37.00 36.70 * 36.60 CS, 70 ° C 84.70 33.40 * 70.30 CS, 40 ° C, Relative Humidity 98% 91.50 70.10 * 83.90 CStr, 50% 4.20 5.40 * 4.20 index 100; * unsatisfactory foam Lupranol® 2042 OH number of 28 milligrams of KOH per gram, polyethylene based on polypropylene oxide and ethylene oxide (BASF) Lupranol® 2047 OH number 42 milligrams of KOH per gram, polyethylene based on propylene oxide and Ethylene oxide (BASF) Lupranol® 4100 OHN 24 milligrams KOH per gram, acrylonitrile / styrene-based polymer polyol (BASF), Lupragen® N201 Amine catalyst (BASF), Lupragen® N206 Amine catalyst (BASF), B 8680 Silicone stabilizer (Goldschmidt), FD (core) Core foam density in kilograms per cubic centimeter, CS Compression adjustment at the indicated temperature measured by the D'Essai Methods 1046, RH Relative atmospheric humidity, CStr 50% Resistance compression - D'Essai 1003 method Examples 5-8 (according to the present invention) Example Example Example 5 6 * 7 8 Lupranol® 2042 53.30 53.30 77.05 55.05 Lupranol® 4100 30.00 30.00 10.00 30.00 Glycerol 0.60 0.60 3.00 3.00 Lupranol® 2047 4.00 4.00 Lupranol® VP 9236 8.50 8.50 Lupranol® VP 9209 5.00 7.00 Lupragen® N201 0.15 0.15 0.30 0.40 Lupragen® N206 0.15 0.15 0.25 0.25 XFH 2584 0.30 B 8680 0.30 0.30 0.40 Water 3.00 3.00 4.00 3.00 FD 40.00 40.00 37.00 36.00 CS, 70 ° C 18.20 25.40 17.50 16.00 CS, 40 ° C, 98% Relative Humidity 30.60 36.40 21.80 23.90 CStr, 50% 8.00 11.20 4.70 5.70 * Index 110 Lupranol® VP 9209 OHN 530 milligrams of KOH per gram, trifunctional polyol based in ethylene oxide (BASF), Lupranol® VP 9236 OHN 605 milligrams of KOH per gram, trifunctional polyol based on ethylene oxide (BASF), XFH 2584 Dabco XHF 2584 - silicone stabilizer (Air Products)

Claims (11)

R E I V I N D I C A C I O N E S:

1. A process for producing polyurethane foams by reacting a) diisocyanates and / or organic and / or modified organic polyisocyanates, with b) at least one relatively high molecular weight compound containing at least two reactive hydrogen atoms, c) by at least one compound containing from three to eight, preferably from three to six reactive hydrogen atoms, and d) chain lowering and / or low molecular weight crosslinking agents containing at least two reactive hydrogen atoms in the presence of e) swelling agents f) catalysts and, if desired, g) auxiliaries and additional additives. wherein (c) are adducts rich in ethylene oxide having an ethylene oxide content of more than 50 weight percent, and an OH number of 200 to 800 milligrams of KOH per gram, and (d) are agents polyfunctional chain and / or crosslinking extenders having an OH number of more than 700 milligrams of KOH per gram.

2. A process according to claim 1, wherein the compounds (c) of relatively high functionality are used in proportions of 0.5 percent to 10 percent by weight, based on the weight of the components (b) to (g).

3. A process according to claim 1, wherein the compounds (c) of relatively high functionality are used in proportions of 1 percent to 8 percent by weight, based on the weight of the components (b) to (g) ).

4. A process according to claim 1, wherein the polyfunctional chain and / or crosslinking elongation agents (d) are used in proportions of 0.5 percent to 6 percent by weight based on the weight of the components ( b) a (g).

5. A process according to claim 1, wherein the polyfunctional chain and / or crosslinking elongation agents (d) are used in proportions of 0.5 percent to 4 percent by weight based on the weight of the components ( b) a (g).

6. A process according to claim 1, wherein the molar ratio of (c) to (d) is within the range of 10 to 0.3, preferably 3.0 to 0.3.

7. A process according to claim 1, wherein the component (c) preferably used comprises adducts of ethylene oxide of glycerol, trimethylolpropane, pentaerythritol or mixtures thereof.

8. A process according to claim 1, wherein the component (d) used is glycerol.

9. A polyurethane foam comprising at least one relatively high molecular weight compound containing at least two reactive hydrogen atoms (b) and at least one combination of at least one compound containing from 3 to 8 , preferably from 3 to 6 reactive hydrogen atoms (c) and at least one low molecular weight chain and / or crosslinking agent containing at least two reactive hydrogen atoms (d), wherein the component (c) used comprises adducts rich in ethylene oxide having an ethylene oxide content of more than 50 weight percent and an OH number of 200 to 800 milligrams of KOH per gram in proportions of 0.5 to 10 percent. percent by weight, based on the weight of the components (b) to (g), and the component (d) used comprises polyfunctional chain and / or crosslinking elongating agents having an OH number of more than 70 milligrams of KOH per gram in proportion ions of 0.5 percent to 6 percent by weight, based on the weight of components (b) to (g).

10. A polyurethane foam according to claim 9, wherein the components (c) and (d) are used in a molar ratio of 10 to 0.3, preferably 3.0 to 0.3.

11. The use of a polyurethane foam according to claim 9, as an upholstery material in the furniture or automobile sector. SUMMARY OF THE INVENTION Polyurethane foams are produced by reacting a) diisocyanates and / or organic and / or modified organic polyisocyanates, with b) at least one relatively high molecular weight compound containing at least two reactive hydrogen atoms, c) at least one compound contains from three to eight, preferably from three to six reactive hydrogen atoms, and chain-lowering and / or low molecular weight crosslinking agents containing at least two reactive hydrogen atoms in the presence of e) swelling agents f) catalysts and, if desired, g) auxiliaries and auxiliary additives. wherein (c) are adducts rich in ethylene oxide having an ethylene oxide content of more than 50 weight percent, and an OH number of 200 to 800 milligrams of KOH per gram, and (d) are agents of chain lengthening and / or polyfunctional crosslinking having an OH number of more than 700 milligrams of KOH per gram. The polyurethane foam produced by this process can be used as an upholstery material.